The present invention relates to a night vision arrangement in the form of a device for the enhancement of night vision of a vehicle, such as an automobile.
It has been proposed previously to provide a night vision arrangement in an automobile. U.S. Pat. No. 5,414,439 discloses an arrangement in which a vehicle is equipped with an infra-red sensitive camera which is directed to capture an image of the roadway in front of the vehicle. The camera provides an output in the form of a video signal which is processed by a video processor, and which is then passed to a head-up display. It has been known previously to provide head-up display units in vehicles such as combat aircraft to enable the pilots of the aircraft to view, simultaneously, the scene on the exterior of the aircraft, and also an image projected on to the head-up display. U.S. Pat. No. 5,414,439 utilises a head-up display of this general type to enable the driver of the vehicle to view the road in front of the vehicle and, simultaneously, to see an image derived from the infra-red camera.
In the arrangement of U.S. Pat. No. 5,414,439, the windshield is provided with a semi-transparent mirror which is utilised as a combiner to combine the real image of the road in front of the vehicle as viewed by the driver, and a virtual image of the road ahead.
The infra-red sensitive camera of U.S. Pat. No. 5,414,439 is of conventional design incorporating a lens arrangement which serves to focus an image on a relatively large sensor element which is located in alignment with the optical axis of the lens arrangement. The entire camera is rather bulky and the positioning of the camera is shown, schematically, with the camera being mounted within the engine compartment of the vehicle.
The present invention seeks to provide an improved night vision arrangement.